Designation D2764 − 99 (Reapproved 2015)´1 Standard Test Method for Dimethylformamide Insoluble (DMF I) Content of Tar and Pitch1 This standard is issued under the fixed designation D2764; the number[.]
Trang 1Designation: D2764−99 (Reapproved 2015)
Standard Test Method for
Dimethylformamide-Insoluble (DMF-I) Content of Tar and
Pitch1
This standard is issued under the fixed designation D2764; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε 1 NOTE—SI units formatting was corrected editorially in May 2015.
1 Scope
1.1 This test method covers the determination of the
dimethylformamide-insoluble matter (DMF-I) in tar and pitch
1.2 Since this test method is empirical, strict adherence to
all details of the procedure is necessary
1.3 The values stated in inch-pound units are to be regarded
as standard The values given in parentheses are mathematical
conversions to SI units that are provided for information only
and are not considered standard
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use It is the
responsibility of the user of this standard to establish
appro-priate safety and health practices and determine the
applica-bility of regulatory limitations prior to use For specific hazard
information, see Sections 6and7
2 Referenced Documents
2.1 ASTM Standards:2
D329Specification for Acetone
D370Practice for Dehydration of Oil-Type Preservatives
D4072Test Method for Toluene-Insoluble (TI) Content of
Tar and Pitch
D4296Practice for Sampling Pitch
E11Specification for Woven Wire Test Sieve Cloth and Test
Sieves
3 Summary of Test Method
3.1 A sample is digested in hot DMF and filtered Any
insoluble matter is washed, dried, and weighed
4 Significance and Use
4.1 This test method is useful in evaluating and character-izing tars and pitches and as one element in establishing the uniformity of shipments or sources of supply It is a rapid and reasonably accurate measure of the toluene insoluble (TI) content of tar and pitch Test MethodD4072
5 Apparatus
5.1 Filtering Crucible, porcelain, with fine-porosity bottom,
30 mL to 40 mL capacity, high form, maximum pore diameter
7 µm
5.2 Filter Apparatus—Filter flask and tube with crucible
adapter
5.3 Sieves, U.S Standard 600 µm (No 30) and 250 µm (No.
60), conforming to Specification E11
5.4 Water Bath, maintained at 203 °F to 212 °F (95 °C to
100 °C)
6 Reagents and Materials
6.1 Dimethylformamide, reagent grade, boiling range 4 °F
(2 °C) including 307 °F (153 °C) Store over a suitable desic-cant Decant immediately before use If necessary, filter through a plug of glass wool or absorbent cotton until optically clear
6.2 Acetone, meeting Specification D329 (Warning—
Flammable Health hazard.)
6.3 Concentrated Hydrochloric Acid.
6.4 Celite Analytical Filter Aid (CAFA)—Dry to constant
mass at 22 °F (105 °C) and store in tightly stoppered container
N OTE 1—Do not use any other grade of filtering medium because porosities differ.
7 Hazards
7.1 Fumes of the solvents should be removed by means of proper hoods from all working areas The working area should
be kept free of sparks and flames DMF fumes should not be inhaled, and prolonged contact of DMF with the skin should be avoided
1 This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
Current edition approved April 1, 2015 Published May 2015 Originally
approved in 1968 Last previous edition approved in 2009 as D2764 – 99 (2009).
DOI: 10.1520/D2764-99R15E01.
2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959 United States
Trang 27.2 Observe proper laboratory procedures for handling and
diluting hydrochloric acid
8 Bulk Sampling
8.1 Samples from shipments shall be taken in accordance
with Practice D4296 and shall be free of foreign substances
The sample shall be thoroughly mixed immediately before
removing a representative portion for the determination or for
dehydration
9 Dehydration of Sample
9.1 Hard Pitch—If the solid bulk sample contains free
water, air-dry a representative portion in a forced draft oven at
50 °C
9.2 Soft Pitch—If the presence of water is indicated by
surface foam on heating, maintain a representative portion of
the bulk sample at a temperature between 257 °F and 302 °F
(125 °C and 150 °C) in an open container until the surface is
free of foam Take care not to overheat, and remove heat source
immediately when foam subsides
9.3 Tar—Dehydrate a representative portion of the bulk
sample in accordance with Test Method D370, but stop the
distillation when the temperature reaches 338 °F (170 °C)
Separate any oil from the water that has distilled over (if
crystals are present, warm sufficiently to ensure their solution),
and thoroughly mix the oil with the residual tar in the still after
the latter has cooled to a moderate temperature
10 Preparation of Working Sample
10.1 Hard Pitch—If the pitch can be crushed at room
temperature, prepare a 20 g working sample by suitable
crushing, mixing, and quartering of a representative portion of
the dry sample The crushing can be done with a small jaw
crusher and a mullite mortar and pestle No particle in the
representative sample shall be larger than 5 mm in any
dimen-sion Crush this sample so that all of it will pass the 250 µm
(No 60) sieve but have a minimum of fine particles Store the
sieved working sample in a tightly closed container and use
within 24 h (see10.4)
10.2 Soft Pitch—If the pitch is too soft to grind and too
sticky to mix, heat a representative portion of the dry sample to
the lowest temperature that will permit passage through the
600 µm (No 30) sieve, taking care to avoid excessive loss of
volatile matter Do not exceed 10 min for this melting period
Pass the heated sample through the 600 µm sieve to remove
foreign matter
10.3 Tar—Heat a representative portion of the dry tar to the
lowest temperature that will permit passage through the
600 µm (No 30) sieve, then filter through this sieve to remove
foreign matter
10.4 Preservation of Working Samples—Store samples as
large lumps or as solidified melts in closed containers Discard
working samples 24 h after crushing and sieving since changes
in composition sometimes occur in pulverized pitch
11 Crucible Preparation
11.1 If the crucible, after thorough cleaning (11.2), has been
used for less than six determinations, clean it as follows
Remove the mat, wash the crucible with distilled water, dry, and ignite in a muffle furnace for 1 h at about 1472 °F (800 °C) Cool the crucible slowly by placing it in a drying oven for 1 h after removal from the furnace to prevent cracking and place it in a desiccator while still warm
11.2 After the crucible has been used for six determinations, remove any residual ash from pores in the filtering area by boiling in 1 + 1 hydrochloric acid Add equal volume of concentrated hydrochloric acid to distilled water Then boil the crucible in distilled water, thoroughly back wash with distilled water, dry, and ignite as in11.1
12 Procedure
12.1 Make and record all weighings to the nearest 0.5 mg 12.2 Transfer 0.45 g to 0.55 g of Celite to a clean, filtering crucible Distribute the Celite evenly over the bottom Dry in
an oven at 221 °F to 230 °F (105 °C to 110 °C) for 30 min Cool in a desiccator and weigh Record the mass of crucible plus Celite
12.3 Transfer 0.45 g to 0.55 g of previously dried Celite to
a clean, dry, and tared 100 mL beaker and weigh Record the mass of Celite Place 0.5 g of working sample in the same beaker and reweigh Calculate and record the mass of the sample
12.4 Add 25 mL of dry dimethylformamide (DMF) to the
beaker while stirring the mixture with a stirring rod or thermometer to break up lumps, then cover the beaker with a small watch glass Place the beaker and a wash bottle contain-ing DMF in a water bath maintained at 203 °F to 212 °F (95 °C
to 100 °C) (A suitable mass can be used to keep the beaker from being upset in the water bath.) Digest for at least 30 min Occasionally stir the contents of the beaker to promote digestion Check for completeness of digestion by inspecting the bottom of the beaker for undigested pitch or tar
12.5 Insert the filter tube with adapter into the filter flask and place the previously prepared and tared crucible in the adapter Carefully add sufficient DMF to the crucible to wet the Celite thoroughly Apply suction, and form a mat of evenly distributed Celite Maintain suction until filtration and subse-quent washing with DMF are completed
12.6 Pour the hot DMF-pitch mixture into the crucible, while the Celite in the crucible is still wet without disturbing the mat Stir the mixture in the beaker immediately before pouring successive portions into the crucible Allow the con-tents to drain completely, but not to the extent that the insoluble material on the filter appears substantially dry
12.7 Wash the beaker, thermometer or stirring rod, and crucible with small portions (2 mL to 3 mL each) of DMF at
203 °F to 212 °F (95 °C to 100 °C) from the wash bottle Pass all the washes through the filter Allow each wash to pass almost completely through the filter before the next is added Use a suitable policeman to sweep the insoluble particles into the crucible Repeat the DMF washes until the filtrate is the same color as the DMF used for washing Twelve washings are usually enough
Trang 312.8 Discontinue the suction Fill the crucible with acetone;
reapply suction until the solvent has passed through the filter,
then discontinue suction and repeat the operation with fresh
acetone three more times Maintain full suction for a minimum
of 5 min after the last acetone wash Remove the crucible and
wipe the outside with a clean, soft cloth or tissue moistened
with acetone
12.9 Place the filtering crucible in the drying oven at 222 °F
to 230 °F (105 °C to 110 °C) and dry to constant mass
(60.5 mg) When the hot crucible is removed from the drying
oven, it should have no odor of DMF (Note 1) Transfer the
crucible to the desiccator and cool for 25 min, then weigh and
record the mass of the filtering crucible and its contents
N OTE 2—Insoluble matter on the filter, after washing with acetone,
should have no odor of DMF, which is evidence of insufficient washing.
If odor of DMF is detectable, repeat the entire determination.
13 Calculation
13.1 Calculate the DMF-insoluble (DMF-I) content as
fol-lows:
DMF 2 I, % 5@~A 2 B 2 C!/D#3100
where:
A = total mass of the filtering crucible, Celite (added to the
crucible and to the sample), plus DMF insoluble matter
B = initial mass of the filtering crucible containing dried
Celite,
C = mass of dry Celite added to the sample, and
D = mass of working sample used for the determination
14 Report
14.1 Report the percentage of matter insoluble in dimethyl-formamide (DMF-I) to the nearest 0.1 % Duplicate runs that agree within 1.0 % absolute are acceptable for averaging (95 % confidence level)
15 Precision and Bias
15.1 The following criteria should be used for judging the acceptability of results
15.1.1 Repeatability—The average difference between two
results (each the average of duplicate determinations), obtained
by the same analyst on different days, will approximate 0.4 % Two such values should be considered suspect (95 % confi-dence level) if they differ by more than 1.0 % absolute
15.1.2 Reproducibility—The average difference between
two results (each the average of duplicate determinations), obtained by analysts in different laboratories, will approximate 0.8 % Two such values should be considered suspect (95 % confidence level) if they differ by more than 2.5 % absolute
15.2 Bias—This test method has no bias because the value
of DMF-1 is defined in terms of this test method
16 Keywords
16.1 dimethylformamide; insoluble; insoluble matter; pitch; tar
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